With a robber’s arm wrapped around her neck and a gun pointed at her head, a pawn shop employee grabbed the handgun and ran just before Metro Police officers shot and wounded the man as he reached for a rifle, authorities said.

“He selected a victim intending to use her as a hostage to effect his escape,” Clark County Assistant Sheriff Brett Zimmerman said of Monday’s incident. “However, he selected the wrong person.”

Not only did the woman’s split-second decision likely save her life, it allowed three officers to open fire on Mario Trejo, 27, as he reached for the rifle hanging from his shoulder, said Zimmerman, who played video footage of the dramatic incident.

The episode, which started as an armed robbery, unfolded about 1 p.m. at the Super Pawn shop at 1150 S. Rainbow Blvd., near Charleston Boulevard, Zimmerman said. Employees trapped in the store, some of them hiding, called police, he said.

Trejo, who was wearing a motorcycle helmet, grabbed cash and jewelry and was trying to force a manager to open a safe when officers arrived, Zimmerman said.

Shortly after officers arrived, Trejo walked out of the store, pulling the woman toward a car. He had one arm around her neck and pointed the gun to her head with his other hand.

A struggle ensued near the car and the woman, whom Zimmerman said was familiar with guns, grabbed the weapon as a round fired into the ground. She took out the magazine, dropped the gun on the ground and ran.

Officers Thomas Carrigy, 36, Brian Farrington, 48, and Keenan Graham, 23, immediately opened fire on Trejo, who was struck once in the chest, police said.

Trejo was taken into custody with the help of a police dog after he refused to move away from the rifle, Zimmerman said. Trejo was taken to University Medical Center and booked in absentia at the Clark County Detention Center.